Engine synchronization apparatus and control method thereof

Abstract

An engine synchronization apparatus includes: a crank shaft position sensor detecting a position of a crank shaft to detect a tooth and a missing tooth; a cam sensor detecting a position of a cam corresponding to an angle of rotation of each of an intake cam and an exhaust cam; and a controller synchronizing the engine to use a tooth detection signal from the crank shaft position sensor and a cam signal from the cam sensor. The controller carries out an engine synchronization by determining the position of the crank shaft and the position of the cam to select one cam between the intake cam and the exhaust cam and to detect the position of a unique part of the cam signal from a voltage level and a level length of the cam signal of the selected cam.

Claims

1. An engine synchronization apparatus, comprising: a crank shaft position sensor detecting a position of a crank shaft to detect a tooth and a missing tooth which are formed at the crank shaft; a cam sensor, which includes an intake cam sensor and an exhaust cam sensor, detecting a position of a cam corresponding to an angle of rotation of each of an intake cam and an exhaust cam which operate in sync with an engine rotary shaft by detecting an edge of the cam; and a controller synchronizing the engine to use a tooth detection signal from the crank shaft position sensor and a cam signal from the cam sensor, wherein the controller carries out an engine synchronization by searching a unique part of the cam signal from a change pattern of a voltage level and a level length, which is a signal length while a same level is maintained, of the cam signal of the a cam selected among the intake cam and the exhaust cam, and by determining the position of the crank shaft and the position of the cam by comparing the unique part to a previously stored characteristic value of the cam.

2. The apparatus of claim 1, wherein the controller carries out the engine synchronization based on the cam signal of the cam wherein the position of the unique part of the cam signal between the intake cam and the exhaust cam is first determined.

3. The apparatus of claim 2, wherein the controller carries out the engine synchronization by using position information of a corresponding missing tooth when the detection of the missing tooth is determined by the crank shaft position sensor.

4. The apparatus of claim 2, wherein the controller determines whether or not the detected voltage level is valid to determine whether the voltage level of the cam signal is valid for a next level.

5. The apparatus of claim 1, wherein when the position of the unique part of the cam signal is not determined using only the voltage level and the level length which are measured by the cam sensor, the position of the unique part of the cam signal can be determined using a sequential relationship between a previously measured voltage level and level length and a currently measured voltage level and level length.

6. An engine synchronization method, wherein an engine synchronization is carried out using a crank shaft position sensor detecting a position of a crank shaft by detecting one or more teeth and a missing tooth which are installed at the crank shaft and a cam sensor, which comprises an intake cam sensor and an exhaust cam sensor, detecting a position of an edge of a cam corresponding to an angle of rotation of each of an intake cam and an exhaust cam which operate in sync with an engine rotary shaft, the method comprising: receiving, by a controller, a cam signal from the cam sensor of each of the intake cam and the exhaust cam; determining, by the controller, whether or not the missing tooth of the crank shaft is detected by the crank shaft position sensor; searching, by the controller, a unique part of the cam signal from a change pattern of a voltage level and a level length, which is a signal length while a same level is maintained, of the cam signal of the cam selected among the intake cam and the exhaust cam, determining, by the controller, a cam position to compare the unique part to a previously stored position information of a unique part of the cam signal when the detection of the missing tooth of the crank shaft is not determined; and synchronizing, by the controller, the engine using the determined cam position information.

7. The method of claim 6, wherein the engine is synchronized based on a cam signal of the cam wherein the position of the unique part of the cam signal is first determined, among the earn signals received from the intake cam and the exhaust cam.

8. The method of claim 6, wherein the position information of a corresponding missing tooth is used when the detection of the missing tooth is determined by the crank shaft position sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view illustrating a configuration of an engine synchronization apparatus according to the present disclosure.

(2) FIG. 2 is a flow chart for describing a control method of an engine synchronization apparatus according to the present disclosure.

(3) FIG. 3 is a view illustrating a cam signal characteristic of each of an intake cam and an exhaust cam which are formed in a half-moon type according to the present disclosure.

(4) FIG. 4 is a view illustrating a cam signal characteristic of each of an intake cam and an exhaust cam which are formed in a 4-flank type according to the present disclosure.

(5) FIG. 5 is a view illustrating an example of the present disclosure wherein a quick sync is carried out using an exhaust cam when an error occurs at an intake cam according to the present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

(6) The terms and words used in the specification and claims should not be construed as their ordinary or dictionary sense. On the basis of the principle that the inventor can define the appropriate concept of a term in order to describe his/her own invention in the best way, it should be construed as meaning and concepts for complying with the technical idea of the present disclosure. Accordingly, the embodiments described in the present specification and the construction shown in the drawings are nothing but one embodiment in the present disclosure, and it does not cover all the technical ideas of the invention. Thus, it should be understood that various changes and modifications may be made at the time of filing the present application. In addition, detailed descriptions of functions and constructions well known in the art may be omitted to avoid unnecessarily obscuring the gist of the present disclosure. Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings.

(7) The embodiments in the present disclosure will be described in detail with reference to the accompanying drawings.

(8) FIG. 1 is a view illustrating a configuration of an engine synchronization apparatus according to the present disclosure.

(9) As illustrated in FIG. 1, the engine synchronization apparatus according to the present invention may include, but is not limited to, a cam sensor 100, a crank shaft position sensor 200, and a controller 300.

(10) The cam sensor 100 is configured to detect an edge of a cam during the rotation of a camshaft of each of an intake cam and an exhaust cam and output the detected edge to the controller 300 in the form of a pulse type cam signal the voltage phase of which is inverted between the high level (H) and the low level (L). For example, when a cam 110 positions higher than a line (L1) indicated by the dotted line, the output of the cam sensor 100 is a high level (H), and when the cam 110 positions lower than the line (L1), the output of the cam sensor 100 is a low level (L). Here, the cam 110 is provided to open and close the intake valve and the exhaust valve disposed in a combustion chamber, and the camshaft rotates in sync with the crank shaft.

(11) The crank shaft position sensor 200 may be disposed near a sensor wheel 210 provided coaxial with the crank shaft. The sensor wheel 210 may include a plurality of teeth 220 along an outer circumference thereof. The crank shaft position sensor 200 is able to detect protrusion-shaped teeth, detect the angle of rotation and revolution of the crank shaft, and output a result thereof to the controller 300 in the form of a pulse type crank signal. Here, teeth are not formed at the whole circumferential direction portions of the sensor wheel 210, namely, the teeth are formed partially missed. The crank shaft position sensor 200 will recognize the above partially missed tooth portions as a missing tooth 230.

(12) The controller 300 will receive a cam signal and a crank signal from the cam sensor 100 and the crank shaft position sensor 200 and determine the crank position and the cam position using a received result. The controller 300 will control a high pressure fuel pump 400, an injector 500 and an ignition plug 600 using the determined crank position and cam position information, thus carrying out a control to synchronize the fuel injection time and the ignition time of each cylinder of the engine.

(13) More specifically, the controller 300 will compare the information on the level, the level length and the presence of the missing tooth within the level length section to the information on a previously stored cam characteristic information and judge an innate unique part of the cam signal shape, during which when not using the information on the inclusion of the missing tooth based on a missing tooth area non-determination of the crank shaft, the position of the unique part can be recognized using the information on the level and the level length. If the above-mentioned recognition is not available, the engine synchronization can be carried out in such a way to determine the position of the unique part with the aid of a combination of the accumulated cam signal shapes.

(14) The cam is able to transmit an innate type signal based on the shapes and kinds thereof. FIG. 3 illustrates a cam signal which corresponds to one of the above various types.

(15) Since the cam 110 may rotate at a constant speed over 360, the signal outputted from the cam sensor 100 may be divided into a constant low level (L) time and a high level (H) time. As described above, the camshaft is able to rotate in sync with the crank shaft. When the crank shaft rotate two rounds, the camshaft will rotate one round. As illustrated in FIG. 3, it therefore is possible to set in order for the missing teeth of the crank signals to be detected at a predetermined time between the low level time and the high level time of the cam signal.

(16) Since the information on the level of the cam signal at the time when the level distribution and the level length of the cam signal as illustrated in FIG. 3 and FIG. 4 and the missing tooth of the crank signal are detected may have innate values, which are different with respect to the kinds and shapes of the cam, when the crank shaft is at a predetermined rotation position, the crank position at a corresponding time can be determined in such a way to compare, to a previously stored characteristic value, the information on the level distribution and the level length of the measured cam signal and the level of the cam signal at a time where the missing tooth of the crank signal is detected.

(17) The controller 300 of the engine synchronization apparatus according to the present disclosure is able to receive a cam signal from each of the intake cam and the exhaust cam, select an appropriate cam signal between them and synchronize the engine based on the information on a corresponding cam signal.

(18) The control method of the controller of the engine synchronization apparatus according to the present invention will be described in detail with reference to FIG. 2.

(19) The controller 300 may receive a cam signal from each of the intake cam sensor and the exhaust cam sensor (S10). The cam sensor 100 may transmit to the controller 300 the cam signal the voltage waveform of which changes between the high level W) and the low level (L) based on the rotation of the cam 110.

(20) Next, the controller 300 may judge whether or not the position of the missing tooth 230 has been detected from a crank signal from the crank shaft position sensor 200 (S20). As illustrated in FIG. 1, the missing tooth 230 may be formed in such a way that some teeth 220 are partially missing at a predetermined section on the outer circumference of the sensor wheel 210. The signal corresponding to the missing teeth will have a period of over 2 times as compared to the other portions, for which the presence of the missing tooth 230 can be detected. If it is judged that the position of the missing tooth 230 is not currently detected, the controller 300 will search for any unique part from the cam signal so as to carry out the engine synchronization by using only the cam signal.

(21) The controller 300 may judge whether or not the direction of the level of the cam signal has changed (H.fwdarw.L or L.fwdarw.H) (S30). In the above-described occasion, the cam shape is recognized in such a way to confirm only the shift of the signal level and then confirm the level with the inverted value with respect to the previous level valve, without considering the direction (H.fwdarw.L, L.fwdarw.H) of the signal level. If there is a signal level shift, it may seem to be appropriate to change into the level (L) which is inverted from the previous level (H), errors may occur in the following situations.

(22) If a signal level generates in a state where the previous level (H) is recognized, but it is not detected due to an error during the signal level shift, the level of the original cam shape will become (H) by simply inverting the level value, but the value of the signal level that the ECU is recognizing is (L). Since the original cam shape is different to the information that the ECU is currently recognizing, an engine synchronization error may occur.

(23) As illustrated in FIG. 5, if the mounting time is supposed by the designer's intention to match with the tooth falling time before the missing area in case of the cam edge, an error may occur in the following situation. For this reason, in the present disclosure, the presence of any change on the direction is necessarily checked before the shift of the signal level.

(24) Next, the controller 300 may roughly determine a cam position by analyzing the change pattern of the level of the cam signal and the level length thereof (S40). As described above, the information on the level distribution and the level length of the cam signal and the level of the cam signal at the time when the missing tooth of the crank signal is detected may have an innate value (a unique part) which is different based on the kinds and shapes of the cam when the crank shaft is at an appropriate rotation position. The crank position at a corresponding time therefore can be determined in such a way to compare the information on the level distribution and the level length of the measured cam signal to a previously stored characteristic value.

(25) In case where it is possible to determine a unique part of the cam signal using only the information on the level, and the level length of the currently measured cam signal, the position of the unique part of the cam signal can be determined in such a way to compare, to a unique part of the previously stored cam signal, any sequential relationship between the information on the levels and the level lengths of the cam signals which were previously measured and accumulated, and the information on the level and the level length of the currently measured cam signal.

(26) For example, in case of the control method of the engine synchronization according to the present disclosure, since the crank angle is determined using only the cam signal without detecting the position (a cam signal) of the missing tooth, an error may occur, wherein the positions of the unique parts of the cam signals having the same shape are two (one unique part including a gap signal and the other unique part not including a gap signal). In this case, the current crank angle and the cam position may be estimated in such a way to compare any sequential relationship between the position of the previously measured unique part and the level and the level length of the current cam signal to a previously stored value.

(27) Next, in case where the crank angle and the cam position are supposed to be determined by detecting the voltage level and/or the level length, the controller 300 will carry out the synchronization control of the engine based on the same (S60). The controller 300 will carry out the synchronization control with respect to the fuel injection time and the ignition time of each cylinder in such a way to control the high pressure fuel pump 400, the injector 500, the ignition plug 600, etc. In case of the diesel engine, etc., the synchronization control can be carried out by controlling the fuel supply time and the ignition time.

(28) In particular, the controller 300 according to the present disclosure may receive a cam signal from each of the exhaust cam sensor and the intake cam sensor, analyze the cam signals from both the cam sensors and utilize a result of the analysis for the sake of the engine synchronization with the aid of the cam signal from the cam wherein the position of the unique part of the cam signal has been first recognized. Even when the cam sensor of any of the intake cam and the exhaust cam has an error, the synchronization control can be quickly carried out by using the earn sensor of the other cam.

(29) In the present disclosure, the engine synchronization will be carried out by selecting a cam signal of any of the exhaust cam and the intake cam based on the sequential relationship, for example, the time when the cam edge is detected or the time when the position of the cam can be determined, without utilizing only the cam signal of any of the exhaust cam and the intake cam.

(30) In addition to the sensor error, the present disclosure may be employed to confirm the direction of the signal level to prevent any recognition error of the signal level for a quick start after the operation for clearing the signal level information during the installation and resolve any problem which may occur when engaging the mount within an allowable error range.

(31) As illustrated in FIG. 5, the first gap signal related with the position of the missing tooth positions within the signal debounce section, this gap signal cannot be used for the engine synchronization. In this case, in the example as in FIG. 5, the unique part of the cam signal can be first determined at the exhaust cam rather than the intake cam. The quick sync (a cam sync) is carried out using the cam signal of the exhaust cam, and thereafter when the second gap signal is detected, the engine synchronization can be carried out by performing the full sync by using both the crank signal and the cam signal.

(32) The controller 300 may carry out the control of the engine synchronization in such a way that when the position of the missing tooth 230 is determined by the crank shaft position sensor 200, the specific exhaust and intake cam levels are cross-checked at each point of the first and second missing tooth position determinations, thus determining the first and second specific missing tooth position determination time (S70).

(33) FIG. 3 is a view illustrating a result of the use of the engine synchronization apparatus according to the present disclosure in case where the half-moon type cam is used.

(34) As seen in FIG. 3, a corresponding signal is being ignored due to the signal debounce at the first missing tooth detection position in the crank signal, it cannot be used for the engine synchronization.

(35) In case of the half-moon type cam, since the lengths of the voltage level of the cam signal are same for each pulse, the cam-based quick sync may be carried out by detecting any change in the voltage level. As seen in FIG. 3, in case of the exhaust cam signal, since the cam edge is earlier detected than the intake cam signal, and the determination of the unique part is available, the engine synchronization is carried out using the cam signal of the exhaust cam, and in case where the missing tooth is second detected, the full sync will be carried out using both the cam signal and the crank signal.

(36) FIG. 4 is a view illustrating a result of the use of the engine synchronization apparatus according to the present disclosure in case where the 4-flank type cam is employed.

(37) In case of the 4-flank type cam, different from the half-moon type, since the level lengths are different for each pulse, the position of the unique part of the cam signal can be detected using both the voltage level and the level length.

(38) As illustrated in FIG. 4, according to the engine synchronization apparatus of the present disclosure, since the position of the unique part of the cam signal related with the cam shape is first determined from the intake cam, the quick sync (a cam sync) is first carried out based on the cam signal of the intake cam. Thereafter, in case where the gap signal related with the position of the missing tooth is detected, the full sync may be carried out by combining the crank signal and the cam signal.

(39) The embodiments of the control method of an engine synchronization according to the present disclosure may be carried out assuming that the vehicle engine is a direct injection type gasoline engine. The control method according to the present disclosure is not limited to the vehicle which equips with the direct injection type gasoline engine. Such a control method may be employed to any kinds of the engines including the MPI (Multi-Point Injection) type engine or the diesel engine as long as the injection time and the ignition time can be controlled for the sake of the engine synchronization.

(40) For example, the embodiments of the control method of the engine synchronization according to the present disclosure may be employed to the vehicle which equips with the diesel engine. In this case, the controller for the control of the engine synchronization may carry out the control of the engine synchronization with the aid of the control of the fuel supply time and the compression and ignition time.

(41) While the present disclosure has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.